... saddle bags for the Bonneville are very, very difficult, in terms of appropriate styling and size.
The Bonneville is actually a rather small and elegant design. Most bags are either too big - making the bike look fat-arsed - or just really, really ugly.
As with women (or men), it's important to not just settle on something (someone), because it seems as though the options have run out.
Forget about "Triumph" bags - regardless of style, the quality is really low. For the atrocious price, you can instead get something of high quality, custom made, that will last for many years. "Triumph" bags cannot survive any hard duty whatsoever.
I agonized over this for some time, poured over designs and measurements, and, refusing to settle on "imported" bags of low quality designed evidently for 1960's biker gangs, finally found small-town American leather workers who understood what is required for the authentic, practical leather saddle bag that lasts a lifetime. Bags made by American bikers are going to be better in every way than those made by Asian "slave laborers".
I'm happy to refer you to the folks I know - just PM me - but I'm sure that google can help also.